September 30. I need to write all of this down in a longer piece. Just noting here: It was the most exhausting thing I’ve ever done.

Got up at quarter past four, left at quarter past six at sunrise at the South Kaibab Trailhead. When we got to the red zone inside the canyon four hours later, I collapsed just before Phantom Ranch with some kind of heat exhaustion and was pretty scared I’d never get out of there unless by helicopter. Ed, the biologist who studies fish in the canyon and happened to come along the way, took matters into his own hands and made sure I recovered, including bathing in a crystal clear bubbling stream, delightful conditions to be exact.

Set off again three and a half hours later, in a state that was actually already exhaustion. Often thought of the signs at the start of the trails: Down is Optional, Up is Mandatory. Two-thirds of the way – the hard two-thirds – were still ahead of us.

There was never any doubt that I would make it, the only question would be how long it would take, and how sore my feet would be, and how heavy the backpack would feel when I put it down, and how dreadful it would be to put it back on. Never a doubt? Just as I didn’t know what heat exhaustion felt like before that day, and that it could happen to me, I don’t know when I’ll collapse from exhaustion – because it’s equally clear that I would eventually – and what that feels like.

The distance between me and my son has grown significantly over the past five years. It’s not – he explains to me – that my lungs are getting weaker, because they’re well trained, but that my circulation is getting worse. The arteries are calcifying, and there’s ultimately nothing you can do about it. So I work my way up with an old man’s breathing that sounds unnecessarily shallow and always a bit panicky. I sometimes spend too little energy silencing the sounds of my efforts, my groans, and I’m ashamed of it in front of my son. But most of all, what matters now is making it to the top. When he stops to look at an animal, a special view, I just want to keep my steady rhythm.

Cooled our feet in the water at Indian Garden. Four and a half miles to go, the hardest of all. Three quarters of an hour after we left, the sun sets. From the Three-Mile Resthouse, we need the headlamps. This is not an emergency. There are dozens who complete or even begin their hike in the dark. But we are as if placed into another world, one that consists only of the small white circle of light in front of our feet. In it, sometimes, bugs. Scorpions. Spiders. For two hours we work our way forward like this in the dark, without any orientation except for the mileage on the smartwatch, which grows incredibly slowly.

We also don’t see the Rim ahead of us, that sight that makes the last few meters easier during the day. For an hour we can’t believe it’s still not over. At nine we arrive.

September 29. 15 hours.

September 28. Total rest. Pool. Ranger talk in the evening. Preparations now more clearly resemble a countdown.

September 27. He wants to know, not what I would advise my twenty-two-year-old self today, but whether my twenty-two-year-old self would be disappointed in who I am today. No doubt it would be, but I know better than my twenty-two-year-old self.

First descent, Hermit Trail. It takes us hours to pack up our things and buy provisions in the village. We don’t leave until noon. We want to assess our abilities: 2.8 miles down and 2.8 miles up. My son has something of a spring built into him and cannot be stopped by anything when going uphill. He’s twice as fast as I am, and I’m walking heavily breathing, almost staggering, an old man. But the path has fulfilled its purpose, we know now how to use the equipment and have a better idea what we can expect from ourselves. Tomorrow is a complete rest day, and Thursday the big tour to the river and back.

September 26, Tusayan. Dull from the five-hour drive from Las Vegas. It is eight when we arrive, dark. When we drove up the fifty miles from Williams, I think of the Hopi, who must have led the Spaniards through an equal darkness – everything is so much more equal in the dark. And what kind of perplexity about their own existence those people must have felt five hundred years ago, squatting in the dark or by the fire, and how that perplexity is comparable to mine.

My son criticizes that I write so astonishingly little about some days.

September 25. Back in Manhattan. Packing things for the Grand Canyon. We are much better prepared than last time, but it feels all the more unprofessional to cram all those things that we have absolutely no experience with into the suitcase.

September 24. It’s J’s birthday. Her mother calls. J picks up, even though she has firmly resolved not to do so again. She picks up because she has the inevitable hope that she won’t be disappointed, and yet she is, and her nerves are shot afterwards.

September 23. I find it hard to imagine that my son is not about the same age as me.

September 22. Picked up my son from the airport. Good first evening.

September 21. I haven’t slept badly at all here, next to the large construction site, for the last two years. Even though the construction vehicles often beeped all night, it was the normal soundscape of Manhattan, and no one minded, including me. But now the construction site is often quiet at night. And this morning it was a homeless man yelling at irregular intervals, making sounds like a caveman’s. It was three or four or five, and he was probably keeping thousands of people from sleeping with it. I considered calling the police several times. The sleep of thousands of people had to be worth something, no? But more than that, I hoped someone else would. Finally, a police car came sneaking up Broadway. At each block, it briefly emitted a few bubbling sounds from its siren and sneaked on. But it probably wasn’t for the caveman. Anyone who has problems with that doesn’t need to live in Manhattan.